1. Field of the Invention
The present invention relates to fluorescent lamps, ballasts for fluorescent lamps, and methods of operating fluorescent lamps and ballasts therefore.
2. Description of Related Art
Fluorescent lamps, such as compact fluorescent lamps, contain mercury. The mercury can be in the form of an amalgam rather than a liquid.
Fluorescent lamps exhibit “run-up” when initially turned on. Run-up refers to a gradual increasing of the lamps light output from an initial, low level to a higher, stable level. Run-up is typically finished within the first few minutes of operation of the lamp. However, run-up can be noticeable to a user and is generally undesirable. Thus, there is a need to minimize the run-up exhibited by fluorescent lamps.
Certain fluorescent lamps or light fixtures are adapted to be controlled by advanced light source control devices, such as dimmer switches (e.g., phase cut dimmers) and motion sensors. Such control devices can include microprocessors and/or other circuitry that requires power independently of whether the controlled lamp(s) are ON or OFF. Such control devices require a certain amount of quiescent current flow through the fixture, from which to derive the OFF-state power. However, current flow through the fixture during such an OFF-state can cause abnormal operation (e.g. flashing or flickering) of the lamp(s). Thus, there is a need for improved lighting systems to avoid inadvertent OFF-state flashing while providing quiescent OFF-state current to power advanced lighting control devices.